Method of cleaning tile grout

ABSTRACT

A cleaning tool for cleaning the walls of a swimming pool or other concrete structures. Two different sized aggregate or abrasives are combined with a binder to provide an improved cleaning device. The binder and the aggregates are matched so as to wear at substantially identical rates.

This is continuation of U.S. patent application Ser. No. 09/229,471,filed Jan. 13, 1999, now U.S. Pat. No. 6,180,588, which is a division ofU.S. patent application Ser. No. 08/861,403, filed May 21, 1997, nowU.S. Pat. No. 5,908,350, which is a continuation-in-part of provisionalapplication U.S. No. 60/018,980 filed on Jun. 4, 1996.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to cleaning devices for swimming poolsand concrete, and in particular, to a device for cleaning rust spots,calcium deposits, etc. from swimming pool walls and concrete.

2. Description of the Related Art

In-ground swimming pools are sometimes formed of concrete, gunite orplaster (generally referred to herein as concrete). Algae stains, metalstains, and calcium scale often build up on the walls of swimming pools.Some stains may be removed with a brush or rag, but persistent stainssuch as calcium scale are more difficult to remove. If the swimming poolbecomes extremely stained, it is well known to drain and “acid wash” theentire pool. This typically includes scrubbing the pool walls with adiluted mixture of muriatic acid and water and sometimes the use ofbleach. This, of course, is highly undesirable because tens of thousandsof gallons of water are wasted by emptying the pool, and muriatic acidis dangerous to work with. In addition, in-ground swimming pools arestructurally designed to be filled with water, and when they are emptiedthere is a danger that the hydrostatic pressure underneath the pool cancause the pool floor to crack.

Accordingly, there is a long-felt need in the art for a cleaning devicefor concrete swimming pools, patios, paths, driveways and other concretestructures that can effectively remove stains, and is easy to use andavoids the necessity of draining the pool.

SUMMARY

Accordingly, one object of the present invention is to overcome thedifficulties of the prior art.

The present invention is directed to a cleaning composition for cleaningconcrete pools and other concrete devices. The composition includes anaggregate which is an abrasive that does the cleaning, and a binder thatholds the aggregate together to be used in the cleaning process. Thepresent invention achieves a balance between the performance of theaggregate and the binder in that the aggregate and the bindersubstantially uniformly break down in balance with each other so as toefficiently use the majority or preferably substantially all of eachlayer of aggregate before the binder releases it, and a new layer ispresented. The aggregate must not be harder than the material to becleaned (e.g. the pool wall) and preferably has the ability to fractureso as to continually expose new cutting or cleaning areas.

Accordingly, in one aspect of the invention the cleaning device forswimming pools comprises a handle, and a cleaning composite formed onthe handle including (i) a polymer having an elongation at break of500%, (ii) a first type of aggregate, and (iii) a second type ofaggregate which is smaller than the first type.

Other objects, advantages and features of the invention will becomeapparent to those of ordinary skill in the art upon reading the detaileddescription below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the cleaning tool of the invention.

FIG. 2 is a flow chart of the method of making the cleaning tool of theinvention.

FIG. 3 is a magnified view of the area within circle 3 of FIG. 1.

FIG. 4 is an exploded view of a mold for making the cleaning tool of theinvention.

FIG. 5 is a side view of a second embodiment of the mold.

DETAILED DESCRIPTION

The cleaning tool of the present invention is illustrated in FIG. 1. Itincludes a cleaning portion 1 and a handle 2 extending therefrom. Handle2 is preferably provided with a snap clip 3 for engagement in aconventional manner with a swimming pool accessory extension pole 4.

The cleaning tool is especially useful in removing surface blemishesfrom concrete or plaster pools and ceramic tile at the waterline of thepool. This includes cleaning the grout without scratching or gouging it.Such surface blemishes include rust stains, algae stains, metal stains,swimfin stains, etc. on the pool walls and calcium build-up on ceramictile. The cleaning composition is formed of two different sizedaggregates used as the cleaning or abrasive element of the device and aselected polymer, described more fully below, which tool posts orencases each aggregate particle. As shown in FIG. 3, two different sizesof aggregates are used so that smaller aggregates 6 nest within thespaces between larger aggregates 5. This results in a denser packedconcentration of the aggregate which improves results.

In developing the present invention, the inventor experimented withnumerous types of binders (polymers) and aggregates. Each failed toachieve the superior and unexpected results of the present invention.

Different types of aggregates that were experimented with include:crushed walnut shells, which tended to be too tough, crushed corn cobswhich were too soft, and crushed peach pits which also were too soft.Silicon carbide was used, but it was too hard and sharp, as was aluminumoxide. In addition, the inventor experimented by adding a powdereddetergent to the aggregates, but that was deemed ineffective. Similarly,the inventor experimented by adding sawdust and cloth to the aggregates,but they too were deemed ineffective. Garnet was too sharp, tungstencarbide was too hard, and pumice was too soft.

The use of silica sand as the aggregate achieved the best results forproviding the proper hardness and wearability for concrete.

In addition, experiments were performed with numerous binders. Theseinclude a two-part polyurethane casting system having a shore A hardnessof 50-60 sold by Hexcel Corporation of California. However, the inventorfound that the more suitable binder to achieve the desired balance withthe silica sand was a mold compound marketed by Smooth On Corporationlocated in Gillette, N.J. known as PMC-121 having a shore A hardness of50. Although uncertain, the inventor believes that this product achievessuperior results because of its elongation at break property of 500%.However, other properties, or combinations of properties of the bindermay be the reason why the superior results are achieved. The Smooth OnPMC-121 product has the following properties. A viscosity of 1,400 cps,a specific gravity of 1.04 g/cm³, a specific volume of 26.7 cubic inchesper pound, Utimate tensile strength of 350 PSI, a shore A hardness of50, a compression set of 16.5%, a 100% modulus of 100 PSI, and a tearstrength of 65 PLI.

The materials selected for use in the present invention work incombination such that the binder which holds the aggregate materialwears at substantially the same rate as the aggregate. Thus, as theaggregate wears down and loses its cleaning ability, the binder alsowears down until the spent aggregate and binder fall off the device. Asa result, a new layer of aggregate and binder are exposed to, provide anew cleaning surface. As shown in FIG. 3, the use of two sizedaggregates, silica sand #20 and silica sand #30, work together such thatthe smaller silica sand 6 nestles into the spaces between adjacentlarger particles of silica sand 5. The sand is also surrounded by thepolymer 7. Moreover, silica sand is friable and therefore continuallypresents new cutting or cleaning edges to be used in cleaning the poolwall. The above advantages are achieved, in one aspect of the invention,by the following composition.

A composition of matter including the following elements in percentagesby volume: 40% of a polymer having a 50 shore A hardness and anelongation at break of 500%, such as PMC 121/50 marketed by Smooth-OnCorporation of Gillette, N.J. 5% MEK (methyl ethyl ketone), 27½% silicasand no. 20 and 27½% silica sand no. 30.

FIG. 2 illustrates a method of making the cleaning tool of theinvention. As Smooth-On PMC 121 is a two-part polymer, there is a part Aand a part B which must be mixed together to form the product. Typicallythis is done in a pail with plastic spatula. In step 10, part A and partB are mixed at a 1:1 ratio for approximately 1 minute to constitute 40%of the entire volume to be made. Next, in step 20, MEK is added to themix to constitute 5% of the volume of material to be made and the mix iscontinued to be mixed for another minute to two minutes. In step 30,27½% silica sand no. 20 and 27½% silica sand no. 30 are added and themixture is again mixed for a minute or two minutes. In step 40 themixture is poured into a mold and allowed to set for 4-6 hours at roomtemperature. The mold is then released (step 50) and the product allowedto cure for an additional six or seven days (step 60).

FIG. 4 illustrates a mold 70 for use with the invention. As shown, themold 70 has two parts 72 and 74 which join together when the compositionis poured. Each part 72 and 74 have cut-outs 76 formed therein to formthe shape of the molded tool. The top of each part of the mold 70 alsohas a semi-circle 80 a or 80 b formed therein such that when parts 72and 74 are joined together semi-circles 80 a and 80 b form a full circle82. The mold is then poured through the circle 82 and handle 2 is theninserted through the circle 82 into the mold. The mold is released byseparating the two parts 72 and 74 of the mold 70.

FIG. 5 shows an alternate embodiment of the mold 70′ in which multiplemolds are stacked upon each other.

Having thereby described certain embodiments of the invention, it willbe apparent to those skilled in the art that many modifications may bemade within the scope of the invention. Therefore, the scope of theinvention is only limited by the appended claims.

For example, in certain embodiments of the invention, titanium dioxidemay be added to the mix in a small amount to suitably color the finalproduct.

What is claimed is:
 1. A method of cleaning tile grout, comprising:providing a tile grout cleaner including a first type of aggregate thatis friable and a second type of aggregate that is friable, a binder forbinding the first and second types of aggregate together; scrubbing thetile grout with the tile grout cleaner whereby the first and second typeof aggregate and the binder all wear at substantially the same rate. 2.The method of claim 1, wherein the first type of aggregate is silicasand no. 20 and the second type of aggregate is silica no. 30, and thestep of scrubbing includes scrubbing the tile grout with the tile groutcleaner whereby the silica sand no. 20, the silica sand no. 30, and thebinder all wearing at substantially the same rate.
 3. The method ofclaim 1, wherein the binder is a polymer having an elongation to breakof 500%, a tensile strength of 350 PSI and shore A hardness of
 50. 4.The method of claim 1, wherein the tile grout cleaner further comprisesa polymer thinner.
 5. The method of claim 4, wherein the polymer thinneris methyl ethyl ketone.
 6. A method of cleaning tile grout, comprising:providing a tile grout cleaner including more than one type of cleaningelement that is friable and a binder for the more than one cleaningelement together; scrubbing the tile grout with the tile grout cleanerwhereby the more than one type of cleaning element and the binder allwear at substantially the same rate.
 7. The method of claim 6, whereinthe more than one type of cleaning element is more than one type ofsilica sand.